Anagrams of: OCREEP_

• A groove at the ends of the staves of a barrel into which the edge of the head is fitted.

• A cooper's tool for making these grooves.

• President.

• Cousin (usually as a term of address)

• Because

• a large sandwich made of a long crusty roll split lengthwise and filled with meats and cheese (and tomato and onion and lettuce and condiments); different names are used in different sections of the United States

• of or relating to the null set (a set with no members)

• a quantity of no importance; thing (object:), singular, negative pronoun; pronoun, thing, singular; quantifier: negative existential

• a mathematical element that when added to another number yields the same number

• the point on a scale from which positive or negative numerical quantities can be measured

• the sight setting that will cause a projectile to hit the center of the target with no wind blowing

• indicating the absence of any or all units under consideration

• having no measurable or otherwise determinable value

• indicating an initial point or origin

• adjust (an instrument or device) to zero value

• adjust (as by firing under test conditions) the zero of (a gun)

• annoying and unpleasant

• causing a sensation as of things crawling on your skin

• a car suitable for traveling over rough terrain

• a collection of things (goods or works of art etc.) for public display

• the chief executive department of the United States government

• British term for someone who introduces television acts or cabarets etc

• act as a master of ceremonies